Process and apparatus for thermochemically hardening workpieces
AssigneeALD Vacuum Technologies GmbH
InventorsVolker Heuer, Klaus Löser
Life of this patent
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Abstract
A process and apparatus for thermochemically hardening workpieces is provided incorporating the following steps, carried out in a variable sequence: one or more carburizing steps, each in a carbon-containing gas atmosphere at a pressure of less than 50 mbar, the workpieces being held at temperatures of 900 to 1050° C.; if appropriate, one or more diffusion steps, each in a gas atmosphere at a pressure of less than 100 mbar; and one or more nitriding steps, each in a nitrogen-containing discharge plasma at a pressure of less than 50 mbar, the workpieces being held at temperatures of 800 to 1050° C.
Claims39
A process for the thermochemical hardening of workpieces comprising, in a variable order:
- one or more carburizing steps, in each case in a carbon-containing gas atmosphere having a pressure of less than 50 mbar, where the workpieces are maintained at temperatures of from 900 to 1050° C.;
- optionally one or more diffusing steps, in each case in a gas atmosphere having a pressure of less than 100 mbar;
- and
- one or more nitriding steps within low pressure heating chamber(s), in each case in a nitrogen-containing gas atmosphere having a pressure of less than 50 mbar, where the workpieces are maintained at temperatures of from 800 to 1050° C., the nitrogen-containing gas atmosphere contains molecular nitrogen (N2) as donor gas and is excited by a discharge plasma in the low pressure heating chamber(s);
- wherein
- the process is carried out in such a way that time intervals between two successive process steps are shorter than 15 minutes and the workpieces are maintained in a gas atmosphere having a pressure of less than 300 mbar during these time intervals.
Dependencies are inferred from the claim text.